The state that is credited with further opening the doors to legalized sports gambling began taking bets on Thursday.

New Jersey governor Phil Murphy placed the first bets in the state at Monmouth Park Racetrack -- a $20 bet on Germany to win the World Cup and a $20 bet on the New Jersey Devils to win the Stanley Cup next season.

Joining Murphy was former state senator Ray Lesniak, who drafted the New Jersey Sports Betting Act. It was signed into law in 2012, but the state had to wait until last month when the U.S. Supreme Court ruled the Professional and Amateur Sports Protection Act Of 1992 unconstitutional. That allowed the states to unilaterally make their own decisions in regard to sports betting.

The state was beaten to the punch when last Tuesday, the state of Delaware -- which previously offered an NFL parlay card -- began taking its first single-game sports bets.

Sports betting began in Atlantic City as well on Thursday, with Hall of Famer Julius Erving placing the first bet -- a $5 wager on the Philadelphia Eagles to repeat as Super Bowl champions -- at the Borgata race and sports book at 11 a.m.

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Erving told a group of reporters that he thought New Jersey would have a "quick learning curve" and "be successful." He also noted that he wanted to bet on the Philadelphia 76ers, but "it might have been a rules violation," since he works for the team.

New Jersey is expected to be a big betting state. William Hill U.S. chief executive Joe Asher told ESPN that, at maturity, he expects the state to handle roughly $10 billion in bets. Projections, Asher cautions, will depend on a lot of factors including whether the legalization will lead gamblers to leave their bookies.

"People have relationships with their bookies, and I don't want to underestimate that," Asher said.

William Hill is helping the Delaware Lottery operate the sportsbooks, but in New Jersey, the betting outfit is in a joint venture with Monmouth Park.

Hundreds of gamblers flooded Monmouth Park, which has 21 ticket windows where bets can be placed.

Six of those windows are inside its sports bar, which opened on May 10, 2014, in anticipation that legalized sports betting might be around the corner.

The racetrack recently hired 48 people to help facilitate the sports betting operation, including 31 ticket-writers.

New Jersey regulations prohibit anyone under the age of 21 from making a bet and also will take games involving schools in New Jersey, such as Rutgers, off the board.

Like Delaware, New Jersey is expected to offer a mobile betting product soon, with the rule being that all bets must emanate from the state, just like it works in Nevada. New Jersey law also stipulates that gaming operators must wait 30 days after the bill's signing signed to enable online betting.

While the projected money in bets taken at Monmouth would be sizable, William Hill and Monmouth would only net about 4.5 percent of the total handle.

Dennis Drazin, the CEO of Darby Management, which operates Monmouth Park, said he expects the sportsbook to gross 6.8 percent of the handle ($68 million in revenue on $1 billion), after costs, both Monmouth Park and William Hill would walk away with a little more than $20 million. And that's if the market is as robust as projected.

There are no posted limits on bets, but anyone who bets at least $1,000 on a side, like in Delaware, has to allow for the ticket-writer to identify him or her. In Monmouth, anyone who bets more than $1,000 has to have a rewards card to swipe in upon betting.

Monmouth Park's sportsbook will be open Monday through Thursday and Sunday until 1 a.m. and Friday and Saturday until 2 a.m.

Patrons who come to the sportsbook during days and times when horse racing is taking place have to purchase a $5 general admission ticket and pay $5 for parking.